A power grid distributes power by generating electricity at a power generation facility, and then distributing the electricity through a variety of power transmission lines to the power consumer. The power generator in many, if not most, cases consists of one or more spinning electrical generators. Sometimes the spinning generators are driven by a hydroelectric dam, large diesel engines or gas turbines; in many cases the generators are powered by steam.
When the power generator is a so-called spinning electrical generator, i.e., a gas or steam turbine generator, it typically does not operate at peak, i.e., 100% capacity, rather operates, under normal conditions, with a spinning reserve margin, which is the extra generating capacity that is available by increasing the power output of generators that are online, i.e., already running and connected to the electric power generation facility. For most power generators, this increase in power is achieved by increasing the torque applied to the turbine's rotor, for example, by increasing the gas or steam flow or pressure to the turbine. Maintaining a spinning reserve is important to efficient and timely power generation, as increased power demands can be met virtually in real time by employing the spinning reserve capacity. This is in contrast with non-spinning reserve, i.e., extra power generating capacity that is not currently running or connected to the system, which typically can only be brought online with some delay.
Due to the need to have sufficient grid spinning reserve to accommodate, for example, peak demand load requirements, and avoid power disruptions, brownouts, blackouts, etc., grid spinning reserves tend to be maintained at relatively conservative levels, for example, by running numerous gas turbines but maintaining each at a run rate sufficiently below capacity to allow for near instantaneous increased power generation in response to increased demand. Because a spinning electrical generator tends to operate at higher efficiency as it approaches 100% capacity, running below capacity tends to result in inefficiencies, known as grid spinning reserve losses. Accordingly, it would be desirable to minimize grid spinning reserve losses by reducing the reserve margin requirement, while maintaining sufficient spinning reserve to meet anticipated peak loads.